Floyd Mayweather's Tokyo Opponent Is Michael Jordan of Kickboxing, Says RIZIN Star

Floyd Mayweather was right to back out of his MMA fight with Tenshin Nasukawa ... 'cause the kid's the Michael Jordan of kickboxing and Floyd woulda got his ass beat -- so says a RIZIN star.

TMZ Sports spoke with Daron Cruickshank -- who was set to be on the same fight card as Floyd and Tenshin in their NYE tilt in Tokyo -- and he tells us Tenshin's no joke on the mat.

"He's like the Michael Jordan, over there, of kickboxing," Cruickshank says.

Of course ... Floyd bailed on the fight initially in part because he thought it was understood it would be solely a boxing match.

But ... Mayweather says the fight might be back on now that he's made sure it'll be hands ONLY.

Daron says that's a smart move by Money ... saying Floyd woulda gotten SMOKED if they allowed Tenshin's feet to get involved.

"If they did a kickboxing match, I think Tenshin would win. If they did a regular kickboxing match, Tenshin would win."

"But, in a boxing match, I don't think he would stand a chance."

Luckily for all of us ... it looks like we might get to see it go down after all -- 'cause Floyd says, "We're gonna make it happen."